I expect you have some sedimentation filters before water enters your aljibe/tinaco/house
If you have 2 filters, replace the first one with the cleanable/reusable pleated paper filter.
Replace the second with a charcoal filter.
It will remove most odors including the hydrogen sulfide (rotten egg) odor.

The piece you show is a way water is exposed to UV light to kill some biological contaminants. Even if the light is on, it could be old with diminished effectiveness. Yearly replacement is usually recommended. If I came into a rental property, I'd replace it right away. Also, there are probably some "sediment" filters that, where I live, I usually replace every two-three months. I check them monthly since the amount of sediment varies.
Near San Antonio, there is a "Home Services" place (also housing "Handi Mail"), and In central ajijic, there is H2Ole in the plaza with El Torito and West of town in the center with "Pacifica" there is Tech Agua. All can repair and replace bulbs , ballasts, filters, etc.
Some people use Garafons of water for drinking. Some use Reverse Osmosis. Some drink from the tap. Just depends on how strong your body is and how good the source of the water is nad how clean the pipes are ...and...and...and....

If you like tech....
Go to the "tech Cube" bldg in Guadalajara
There are hundreds of places that can fix your phone.
Corner of Av 16 Septiembre and Av Juarez
Parking across street next to Sanborns on the east side on 16 Sept
Have fun

Yes
But formerly from Santander
and now CI Banco
I do it manually - look at the bill - do pago servicios - put in required ID and peso amts and a number from my little "fob" from the bank
Normally get a "receipt" showing that I have successfully requested payment which I print as PDF and save
No problem unless I forget....
Which I did once
Met the CFE guy at the door and persuaded him to give me a day
Ran right to CFE office in Chapala and paid via a machine
Whew....